areology

Areology is the study of the planetMars, the "Martian equivalent of geology," as geocrawler.com phrased it. It comes from Ares, the Greek god of war and equivalent of the Roman god Mars after whom the planet is named. The Oxford English Dictionary has citations for this word starting in 1881; science fiction writers have been using it at least since 1932, but most of the citations found via Google have to do with actual space exploration.